[Talk-ca] Address ranges

[Bob Jonkman]

On 22 Mar 2009 at 12:02 Steve Singer <ssinger_pg at sympatico.ca> wrote
about "Re: [Talk-ca] Address ranges[...]"

>Part of me prefers a scheme that adds address tags directly to the nodes
>that make up the road.
>
>The downside of that is[...]

Another downside is that it doesn't reflect reality (or, rather, it 
reflects reality even less than an arbitrary offset).

I'd rather see generated nodes (as per Richard Weait's suggestion) 
with additional "addr" tags, eg.

building=yes
addr:housenumber=123
addr:type=generated-blockface
addr:offsetlat=0.00003
addr:offsetlon=-0.00001
addr:offsetnodeid=<nodeid>


This would be an indication that it's a suitable candidate for 
replacement with observed data.  If the associated road node is moved, 
the building node doesn't necessarily have to be moved, but could be 
re-calculated (which opens its own can of worms).

One problem is that not all addresses are necessarily buildings.  
Sometimes a park, public square or empty lot has an address.  And all 
buildings aren't necessarily houses, so I'm not sure that 
"housenumber" is the most appropriate tag name.

When I worked at the City of Toronto and had access to their Central 
Property Register database there were different concepts of municipal 
addresses, postal delivery addresses, and courtesy addresses.  I 
expect that GeoBase captures the municipal addresses. 

Also, I'm in favour of generating a small polygon (square) rather than 
a single node.  This fixes Michel Gilbert's rendering problem, and 
also more closely reflects reality. Every building I've been to has 
been more than one-dimensional :-)  Yes, this quadruples the number of 
nodes for house number polygons, but that will also be the case when 
we get around to collecting building data and mapping the building 
outline.  Of course, generating polygons makes interpolation more 
difficult...

--Bob.


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